Next weekend I’m running London Marathon, which I’m really looking forward to. It will be my third marathon but my first in London (Brighton and Edinburgh previously). I had never planned to run but was offered a last minute place by Lucozade Sport via Health & Fitness magazine who I write for, and seeing as London is so difficult to get into (oversubscribed ballot entry and expensive charity places) of course I said yes quicker than I can send the email reply. But I had just under three months to train so it’s been tight to say the least – a bit like cramming before a huge exam.
Interestingly, a year and a half of weight training and CrossFit has made me stronger than I was for my previous marathons so I’ve been able to tackle the long distances without too much risk of injury. All those deadlifts have luckily come in handy!
But long steady runs have had a surprising effect on my body. At the start of the training when I was building up from eight, nine miles to 15 and more I got leaner and noticed some excess weight fall off pretty quickly. However, during the weeks where I was running 18, 19, 20 and 21 miles I noticed things change – I was no longer feeling light or lean but quite the contrary, I felt like I’d filled out a bit despite doing big mileage every weekend.
I’d cut back on CrossFit (from four sessions a week to three) but I didn’t think that was the cause. Could I be imagining it? A quick step on the weights at my parent’s house confirmed I was right as I’d gone up a kilo but endurance training requires good fuel so I put it down to the extra calories I’d been consuming.
Turns out there’s more to it than that. When I saw my sports massage therapist – the brilliant Uju Eze, who is actually a movement specialist because she’s definitely more than just a sports masseuse – she confirmed there is science behind the gain.
“When you run at around 65% of your maximum heart rate for a long, sustained period the body goes into a catabolic state (muscle-wasting) which means it adapts and starts to store fat and use muscle as as fuel instead because it thinks something is wrong and it needs to get ready to survive.”
This, and a number of other reasons are why low intensity steady cardio (otherwise known as LISS which is the opposite of HIIT – high intensity interval training) can actually be the wrong choice of exercise if fat loss is your goal. Here are a few reasons why the body is not in a fat burning state:
- the body adapts to low intensity steady state cardio and eventually doesn’t need as much oxygen or energy to do the workout so it becomes easier and consequently less effective. To keep reaping benefits you’d have to increase the intensity e.g. by either training faster or increasing distance.
- Increasing volume however, could have a detrimental effect in the long run because of a loss of muscle mass (the catabolic effect) which in turn leads to fewer calories burned by the body at rest (the metabolic rate) because muscle burns more calories than fat, and if there’s no change in diet it will eventually lead to fat gain.
- too much cardio can also lead to increased hunger and additionally, fuelling for long runs can often involve high glycemic foods before, during and after the workout which actually suppress fat loss and fat burn.
- long steady state cardio only burns calories during the activity rather and doesn’t change your metabolism. To make changes to your metabolism and experience calories burn up to 24 hours after exercise, studies show HIIT training works because it produces mitochondria (cells where respiration happens) and increases mitochondria activity so your body increases its oxidative capacity.
So it wasn’t all in my head, I was indeed actually holding onto weight. There are more explanations and studies shared about this in this article, Does Cardio Make You Fat and following that, check out this article which compares HIIT vs LISS and explains why high intensity interval training is a better option for fat loss and toning up than low state cardio.
I’m now looking forward to the end of this marathon when I can go back to short, sharp and strength based interval training. However, research shows that some steady state cardio can be good as a means of recovery from high intensity strength training so I won’t be giving up on the steady state cardio just yet – it just won’t be as long as it is now.
And I almost forgot! For those friends and family wishing to donate here’s my marathon Just Giving page which a friend kindly set up for me. Even though I don’t have to raise any money for my entry we thought it was only fair to put a few pounds in the pot as a show of gratitude for my place – I’ll be donating to Parkinson’s UK. Thanks all!